Electrical circuit—Amplifies sound
Overview
Microphone amplifier | Coupling condenser |
Line amplifier
Sound picked up by the microphones is amplified in the analog circuit, which achieves a frequency response that reaches the high frequencies (Figure 2) and enables the wide dynamic range of
The microphone amplifier provided for each channel is Analog Devices’ AD797, which boasts
A variable gain circuit is adopted for amplitude control, thus improving the actual
In the signal line, direct current is removed by Elna’s coupling condenser, which has a separator made of synthetic mica mix paper.
Figure 2: Electrical circuit, frequency response
A
Like the microphone amplifier, the line amplifier, AD8672, is provided by Analog Devices.
Interference between blocks is prevented by placing the analog circuit on a different board from digital circuits and providing separate ± power. The analog circuit also achieves superior linearity so that the recorded sound is output faithfully (Figure 3).
Figure 3: Electrical circuit, linearity
11